The present invention relates generally to an apparatus for adjustably mounting optical elements, such as mirrors, beam splitters, lenses, gratings, and the like. More particularly, the present invention relates to an optical mount which permits adjustment of the height, rotational angle, and axial position of the optical element.
The use of adjustable mounting apparatus for supporting optical components, such as mirrors, beam splitters, lenses, gratings, and the like, is known. Common optical mounting apparatus comprise pair of generally parallel plates, of which one of the plates is fixed to a surface or base and the other plate is adjustably suspended from the first plate. Of particular relevance to the present invention, the second plate may be mounted using a "three-point suspension," where adjustment of the perpendicular distance between the plates at each of the three suspension points can provide for axial and rotational adjustment of the second plate.
An exemplary conventional optical mounting apparatus is illustrated in FIGS. 1 and 2. Such conventional apparatus includes a base plate 10 and a stage plate 12, where the plates are held together by a plurality of springs 14 (one of which is illustrated). Three adjustments screws 16, 18, and 20 are threadably received through the base plate 10 and engage the rear surface (i.e. the surface disposed toward the base plate) of the stage plate 12. In this way, the desired "three-point suspension" mechanism is provided.
An aperture 22 is provided in the stage plate 12 in order to support the desired optical element. Usually, a similar aperture 24 is provided in the base plate 10 so that an unobstructed optical path is formed through the mount.
The three-point suspension system illustrated in FIGS. 1 and 2 is advantageous since it provides for rotation of the optical element mounted in aperture 22 about both the horizontal and vertical axis as well as axial translation of the optical element along the axis normal to the plain defined the base plate 10. Most simply, rotation of the optical element about the vertical axis (relative to the apparatus as illustrated in FIGS. 1 and 2) may be achieved by adjustment of either screws 16 and 18 (by an equal amount) or adjustment of screw 20 alone. Similarly, rotation of the optical element about the horizontal axis may be achieved by adjustment of screws 18 and 20 together or by adjustment of screw 16 alone.
Such a straight forward approach, however, suffers from the drawback that rotation of the optical element also results in translation (usually unintended) of the optical element in the direction perpendicular to the plane defined by base plate 10. To overcome this problem, it is necessary that all three adjustments screws 16, 18, and 20 be adjusted whenever the optical element is to be rotated without a change in its axial position.
For these reasons, it would be desirable to provide improved optical mounting apparatus where the optical element could be rotated about a single axis by adjustment of only a pair of adjustment screws without affecting the axial position of the optical element. It would be particularly desirable if such apparatus were similar to conventional apparatus in most respects but allowed for simplified rotational adjustment of the stage plate.
Optical mounting apparatus as illustrated in FIGS. 1 and 2 are frequently supported on a vertically-adjustable post assembly. Such post assemblies frequently include a cylindrical casing having a rod slidably received therein. The rod may be secured by means of a simple set screw, a split collar having a locking screw, or the like. Generally, however, such locking mechanisms require tightening and/or loosening using a screw element which requires the user to spend at least several seconds each time the height of the rod is to be adjusted. Moreover, the action of locking will often affect the alignment which has just been set, necessitating further alignment. When numerous of fine adjustments are being made, the need to continually tighten and loosen such screw-type locking mechanisms can be most inconvenient.
Thus, it would be desirable to provide optical mounting apparatus having improved vertical locking devices. In particular, it would be desirable if the rod in such apparatus could be freed for vertical adjustment simply by pressing a single button and further if the rod could be relocked by releasing pressure from the button.